Complement activation byin vivoneonatal andin vitroextracorporeal membrane oxygenation

[摘要] Complement activation during extracorporeal membrane oxygenation (ECMO) in newborns can be caused by both the underlying disease processes and by blood contact with the ECMO circuit. We investigated the relative importance of these mechanisms by measuring C3a, C5a and sC5b-9 before, during and after neonatal ECMO in six consecutive newborn patients using enzyme-linked immunoassay. In addition complement activation duringin vitroECMO with repeated flow of the same blood volume was measured using blood from healthy adult donors. C3a increased significantlyin vivoafter 1 h (from 1035 ± 193 to 1865 ± 419 μg/l) andin vitroECMO (from 314 ± 75 to 1962 ± 1062 μg/l). C5a increased during ECMO without significant differences betweenin vivoandin vitroactivation. In neonatal patients, sC5b-9 rose faster thanin vitro, but the rapid increase was also significant forin vitroexperiments (in vivo: from 328 ± 63 to 1623 ± 387 μg/l after 2 h; andin vitro: from 78 ± 32 to 453 ± 179 μg/l after 8 h). After this initial peak at 1-2 h, complement activation decreased gradually until 2-3 days after the initiation of ECMO. We conclude that in newborns the rapid activation of the complement system after the start of ECMO is predominantly caused by contact with artificial surfaces rather than the patient's underlying disease.

[学科分类] 生理学与病理学